Datasheet

© 2007 Microchip Technology Inc. Preliminary DS70165E-page 197
dsPIC33F
16.0 QUADRATURE ENCODER
INTERFACE (QEI) MODULE
This section describes the Quadrature Encoder Inter-
face (QEI) module and associated operational modes.
The QEI module provides the interface to incremental
encoders for obtaining mechanical position data.
The operational features of the QEI include:
• Three input channels for two phase signals and
index pulse
• 16-bit up/down position counter
• Count direction status
• Position Measurement (x2 and x4) mode
• Programmable digital noise filters on inputs
• Alternate 16-bit Timer/Counter mode
• Quadrature Encoder Interface interrupts
These operating modes are determined by setting the
appropriate bits, QEIM<2:0> (QEICON<10:8>).
Figure 16-1 depicts the Quadrature Encoder Interface
block diagram.
FIGURE 16-1: QUADRATURE ENCODER INTERFACE BLOCK DIAGRAM
Note: This data sheet summarizes the features
of this group of dsPIC33F devices. It is not
intended to be a comprehensive reference
source. To complement the information in
this data sheet, refer to the “dsPIC30F
Family Reference Manual” (DS70046).
16-bit Up/Down Counter
Comparator/
Max Count Register
QEA
INDX
0
1
Up/Down
Existing Pin Logic
UPDN
3
QEB
QEIM<2:0>
Mode Select
3
(POSCNT)
(MAXCNT)
PCDOUT
QEIIF
Event
Flag
Reset
Equal
2
T
CY
1
0
TQCS
TQCKPS<1:0>
2
Q
QD
CK
TQGATE
QEIM<2:0>
1
0
Sleep Input
0
1
UPDN_SRC
QEICON<11>
Zero Detect
Synchronize
Det
1, 8, 64, 256
Prescaler
Quadrature
Encoder
Interface Logic
Programmable
Digital Filter
Programmable
Digital Filter
Programmable
Digital Filter